Sulfuric Acid Production on Europa: The Radiolysis of Sulfur in Water Ice

Carlson, R. W.; Anderson, M. S.; Johnson, R. E.; Schulman, M.B.; Yavrouian, A.

doi:10.1006/icar.2002.6858

Cited by 152 publications

(157 citation statements)

References 43 publications

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“…Magnetospheric processes have a much stronger effect on the spatial distribution of compositional units on the icy Galilean satellites than the Saturnian satellites because the fluxes of energetic particles in the Jovian magnetosphere tend to be significantly higher. The conspicuously ice-free nature of the uppermost layer of the trailing hemisphere of Europa (e.g., McCord et al, 1998;Hansen and McCord, 2004 ) is likely due to magnetospheric bombardment: either the result of sputtering (removal) of water ice resulting in the accumulation of a lag deposit of non-ice material or due to the formation and gradual accumulation of sulfuric acid hydrate (e.g., Carlson et al 1999Carlson et al , 2002. A careful study of Fig.…”

Section: Discussionmentioning

confidence: 99%

Magnetospheric considerations for solar system ice state

Paranicas¹,

Hibbitts²,

Kollmann³

et al. 2018

Icarus

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a b s t r a c tThe current lattice configuration of the water ice on the surfaces of the inner satellites of Jupiter and Saturn is likely shaped by many factors. But laboratory experiments have found that energetic proton irradiation can cause a transition in the structure of pure water ice from crystalline to amorphous. It is not known to what extent this process is competitive with other processes in solar system contexts. For example, surface regions that are rich in water ice may be too warm for this effect to be important, even if the energetic proton bombardment rate is very high. In this paper, we make predictions, based on particle flux levels and other considerations, about where in the magnetospheres of Jupiter and Saturn the ∼MeV proton irradiation mechanism should be most relevant. Our results support the conclusions of Hansen and McCord (2004), who related relative level of radiation on the three outer Galilean satellites to the amorphous ice content within the top 1 mm of surface. We argue here that if magnetospheric effects are considered more carefully, the correlation is even more compelling. Crystalline ice is by far the dominant ice state detected on the inner Saturnian satellites and, as we show here, the flux of bombarding energetic protons onto these bodies is much smaller than at the inner Jovian satellites. Therefore, the ice on the Saturnian satellites also corroborates the correlation.

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Section: Discussionmentioning

confidence: 99%

Magnetospheric considerations for solar system ice state

Paranicas¹,

Hibbitts²,

Kollmann³

et al. 2018

Icarus

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“…Thus, most particles trapped within Jupiter's co-rotating magnetosphere preferentially impact the trailing hemisphere, producing the "bullseye" pattern of radiolytically produced hydrated material observed by Galileo NIMS (Near Infrared Mapping Spectrometer) (e.g., Paranicas et al 2001Paranicas et al , 2009Carlson et al 2009). Laboratory investigations of radiolytic chemistry in sulfur-water ice mixtures suggest hydrated sulfuric acid as the dominant product, and indeed this species fits the NIMS spectra well (Carlson et al 1999b(Carlson et al , 2002(Carlson et al , 2005.…”

Section: Introductionmentioning

confidence: 87%

“…These include both high-energy electrons and lower-energy sulfur ions originating from the volcanos of Io (Paranicas et al 2001(Paranicas et al , 2002. The resultant interactions drive much of Europa's known surface chemistry by radiolytically processing the surface and creating several new products (e.g., Carlson et al 2002Carlson et al , 2005Paranicas et al 2009). Europa is tidally locked to Jupiter, and Jupiter rotates much faster than Europa completes its orbit (11.2 hours synodic to Europa versus Europa's 3.55 day orbital period).…”

Section: Introductionmentioning

confidence: 99%

“…To date, much of the compositional information, including that indicative of radiolytic chemistry, has been deduced from NIMS observations (e.g., McCord et al 1998McCord et al , 1999Carlson et al 2002Carlson et al , 2005Carlson et al , 2009Hansen & McCord 2008). In addition to the hypothesized trailing hemisphere sulfuric acid (Carlson et al 1999b), other likely detections include CO 2 at 4.25 m m on both the leading and trailing hemispheres (McCord et al 1998;Smythe 1998;Hand et al 2007;Hansen & McCord 2008) and H 2 O 2 at 3.5 m m on the leading hemisphere (Carlson et al 1999a).…”

Section: Introductionmentioning

confidence: 99%

“…Perhaps the most obvious candidate is SO 2 frost, which has a 3.78 m m absorption (e.g., Nash & Betts 1995) and has been confirmed at UV wavelengths with a trailing hemisphere enhancement (Lane et al 1981;Noll et al 1995;Hendrix et al 1998). SO 2 dominates the 3-4 m m spectrum of Io (e.g., Howell et al 1989;Nash & Betts 1995;Carlson et al 1997) and is an expected product of Iogenic sulfur implantation on Europa (Carlson et al 2002(Carlson et al , 2005.…”

Section: Introductionmentioning

confidence: 99%

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A New Spectral Feature on the Trailing Hemisphere of Europa at 3.78 μm

Trumbo

Brown

Fischer

et al. 2017

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We present hemispherically resolved spectra of the surface of Europa from ∼3.1-4.13 m m , which we obtained using the near-infrared spectrometer NIRSPEC on the Keck II telescope. These include the first high-quality L-band spectra of the surface to extend beyond 4 m m . In our data, we identify a previously unseen spectral feature at 3.78 m m on the trailing hemisphere. The longitudinal distribution of the feature is consistent with that of a radiolytic product created by electron or Iogenic ion bombardment. This feature is coincident with an absorption feature of SO 2 frost seen in both laboratory spectra and spectra of Io. However, the corresponding, typically stronger 4.07 m m feature of SO 2 frost is absent from our data. This result is contrary to the suggested detection of SO 2 at 4.05 m m in Galileo NIMS data of the trailing hemisphere, which was severely affected by radiation noise. We use simple spectral modeling to argue that the 3.78 m m feature is not easily explained by the presence of SO 2 frost on the surface. We explore alternative explanations and discuss other potential candidate species.

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Europa's surface composition from near‐infrared observations: A comparison of results from linear mixture modeling and radiative transfer modeling

Shirley

Jamieson

Dalton

2016

Earth and Space Science

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Quantitative estimates of the abundance of surface materials and of water ice particle grain sizes at five widely separated locations on the surface of Europa have been obtained by two independent methods in order to search for possible discrepancies that may be attributed to differences in the methods employed. Results of radiative transfer (RT) compositional modeling (also known as intimate mixture modeling) from two prior studies are here employed without modification. Areal (or "checkerboard") mixture modeling, also known as linear mixture (LM) modeling, was performed to allow direct comparisons. The failure to model scattering processes (whose effects may be strongly nonlinear) in the LM approach is recognized as a potential source of errors. RT modeling accounts for nonlinear spectral responses due to scattering but is subject to other uncertainties. By comparing abundance estimates for H 2 SO 4 · nH 2 O and water ice, obtained through both methods as applied to identical spectra, we may gain some insight into the importance of "volume scattering" effects for investigations of Europa's surface composition. We find that both methods return similar abundances for each location analyzed; linear correlation coefficients of ≥ 0.98 are found between the derived H 2 SO 4 · nH 2 O and water ice abundances returned by both methods. We thus find no evidence of a significant influence of volume scattering on the compositional solutions obtained by LM modeling for these locations. Some differences in the results obtained for water ice grain sizes are attributed to the limited selection of candidate materials allowed in the RT investigations.

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Sulfuric Acid Production on Europa: The Radiolysis of Sulfur in Water Ice

Cited by 152 publications

References 43 publications

Magnetospheric considerations for solar system ice state

Magnetospheric considerations for solar system ice state

A New Spectral Feature on the Trailing Hemisphere of Europa at 3.78 μm

Europa's surface composition from near‐infrared observations: A comparison of results from linear mixture modeling and radiative transfer modeling

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